Heat exchangers utilizing flattened tubes having ends that are received in conforming tube slots of a header are well known. One concern with such heat exchanger constructions during assembly is the location of the end of the tube relative to the tube slot and associated header. If the tube is inserted too far into the tube slot, it can potentially interfere with the fluid flow through the header, or conversely, if the tube is not inserted far enough, it may fail to form an appropriate bond joint, such as when the construction is brazed or soldered to form a sealed joint between the tube and header.
It is known to modify the end of a tube by material removal and/or substantial deformation or resizing of the ends of the tubes. Examples of such approaches are shown in U.S. Pat. Nos. 5,101,887; 5,052,479; 5,048,602; and 4,825,941. While such approaches may be acceptable, they can require relative elaborate equipment, tooling, and the use of extruded tubes, and do not appear to be applicable to thin walled, welded or roll formed tubes. Accordingly, there is a continuing need for improvement in this area.